1. Field of the Invention
The present invention relates to a wireless local area network(LAN) and to a method of operating the LAN. The LAN may be of any suitable type having particular, but not exclusive, application in short range applications such as may be found in domestic and office environments.
2. Description of the Related Art
A typical LAN may comprise central controller consisting of a controller and a primary station having radio transceiving means, the transmitting range of the primary station defining the radio coverage area of the LAN, and a plurality of secondary stations located in the coverage area and registered with central controller. Each secondary station comprises a radio transceiver. Communication between the primary station and the secondary stations in the LAN is done on a time division duplex basis. However provision is made in the time division protocol for duplex transmission between secondary stations without having to use the primary station. Depending on the environment there may be 2 or more LANs with overlapping coverage areas and also it is possible for a secondary station to be able to roam and to want to seek registration with a LAN although out-of-range with the primary station of that LAN. However because the roaming secondary station is out-of-range it is unable to receive the downlink transmissions from the primary station and in consequence it is unable to determine the framing structure of these transmissions.
An object of the present invention is to enable an out-of-range secondary station to register with the central controller of a LAN it wishes to join.
According to one aspect of the present invention there is provided a method of operating a local area network(LAN) comprising a primary station having a radio transceiving means and a plurality of secondary stations, each secondary station having radio transceiving means, characterised by periodically transmitting wide area control signals, by the primary station initiating transmission of a signal a time interval after the wide area control signal, and by a secondary station which is out-of-range with the primary station and wishing to join the LAN transmitting a signal burst in said predetermined interval.
The present invention provides a method of operating a local area network(LAN) comprising a primary station having a radio transceiving means and a plurality of secondary stations, each having radio transceiving means, characterised in that the primary station operates in accordance with a time division protocol comprising a plurality of concatenated frames, in that a predetermined number of the concatenated frames comprise a superframe, in that a wide area control signal is transmitted, in that a predetermined interval after the wide area control signal the primary station initiates the transmission of a superframe, and in that a secondary station unable to communicate directly with the primary station transmits a signal burst during at least a portion of the predetermined interval for reception by at least one of the secondary stations which is in range of the primary station, said at least one of the secondary stations acting as a relay station for the said secondary station.
The present invention also provides a method of operating a local area network (LAN) comprising a primary station having a radio transceiving means and a plurality of secondary stations, each secondary station having radio transceiving means, characterised by periodically transmitting wide area control signals, by the primary station initiating transmission of a signal after the wide area control signal, the signal comprising a superframe consisting of a plurality of TDMA frames together with a time slot, and a secondary station which is out-of-range with the primary station and wishing to join the LAN transmitting a signal burst in said time slot.
The present invention further provides a method of operating a local area network(LAN) comprising a primary station having a radio transceiving means and a plurality of secondary stations, each secondary station having radio transceiving means, characterised in that the primary station operates in accordance with a time division protocol comprising a plurality of concatenated frames, in that a predetermined number of the concatenated frames comprise a superframe which further includes a time slot, in that a wide area control signal is transmitted, and in that the primary station initiates the transmission of a superframe, wherein a secondary station wishing to join the LAN but unable to communicate directly with the primary station transmits a signal burst in said time slot for reception by at least one of the secondary stations which is in range of the primary station, said at least one of the secondary stations acting as a relay station for the said secondary station.
According to a second aspect of the present invention there is provided a local area network(LAN) comprising a central controller including a primary station having radio transceiving means, a plurality of secondary stations, each secondary station having radio transceiving means, means for transmitting a wide area control signal, the primary station responsive to receipt of the wide area control signal transmitting a message comprising a time slot concatenated with a plurality of frames, said time slot enabling a secondary station which is out of range of the primary station to transmit a signal burst.
By means of the present invention the out-of-range secondary station is able to be synchronised with the stations of the LAN and be able to register with the central controller of the LAN using an already registered secondary station as a relay station.